Make bpf dynamically loadable.
This commit is contained in:
pooka
parent
7393fe922a
commit
b2bb0f38d5
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@ -1,4 +1,4 @@
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/* $NetBSD: bpf.c,v 1.153 2010/01/19 22:08:00 pooka Exp $ */
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/* $NetBSD: bpf.c,v 1.154 2010/01/25 22:18:17 pooka Exp $ */
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/*
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* Copyright (c) 1990, 1991, 1993
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@ -39,7 +39,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.153 2010/01/19 22:08:00 pooka Exp $");
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__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.154 2010/01/25 22:18:17 pooka Exp $");
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#if defined(_KERNEL_OPT)
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#include "opt_bpf.h"
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@ -58,6 +58,8 @@ __KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.153 2010/01/19 22:08:00 pooka Exp $");
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#include <sys/vnode.h>
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#include <sys/queue.h>
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#include <sys/stat.h>
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#include <sys/module.h>
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#include <sys/once.h>
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#include <sys/file.h>
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#include <sys/filedesc.h>
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@ -359,13 +361,8 @@ bpf_detachd(struct bpf_d *d)
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d->bd_bif = 0;
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}
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/*
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* bpfilterattach() is called at boot time.
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*/
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/* ARGSUSED */
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void
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bpfilterattach(int n)
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static int
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doinit(void)
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{
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mutex_init(&bpf_mtx, MUTEX_DEFAULT, IPL_NONE);
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@ -375,6 +372,20 @@ bpfilterattach(int n)
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bpf_gstats.bs_recv = 0;
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bpf_gstats.bs_drop = 0;
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bpf_gstats.bs_capt = 0;
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return 0;
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}
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/*
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* bpfilterattach() is called at boot time.
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*/
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/* ARGSUSED */
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void
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bpfilterattach(int n)
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{
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static ONCE_DECL(control);
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RUN_ONCE(&control, doinit);
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}
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/*
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@ -1910,9 +1921,43 @@ struct bpf_ops bpf_ops_kernel = {
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.bpf_mtap_sl_out = bpf_mtap_sl_out,
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};
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void
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bpf_setops()
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{
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MODULE(MODULE_CLASS_DRIVER, bpf, NULL);
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bpf_ops = &bpf_ops_kernel;
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static int
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bpf_modcmd(modcmd_t cmd, void *arg)
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{
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devmajor_t bmajor, cmajor;
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int error;
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bmajor = cmajor = NODEVMAJOR;
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switch (cmd) {
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case MODULE_CMD_INIT:
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bpfilterattach(0);
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error = devsw_attach("bpf", NULL, &bmajor,
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&bpf_cdevsw, &cmajor);
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if (error == EEXIST)
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error = 0; /* maybe built-in ... improve eventually */
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if (error)
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break;
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bpf_ops_handover_enter(&bpf_ops_kernel);
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atomic_swap_ptr(&bpf_ops, &bpf_ops_kernel);
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bpf_ops_handover_exit();
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break;
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case MODULE_CMD_FINI:
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/*
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* bpf_ops is not (yet) referenced in the callers before
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* attach. maybe other issues too. "safety first".
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*/
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error = EOPNOTSUPP;
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break;
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default:
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error = ENOTTY;
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break;
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}
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return error;
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}
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@ -1,4 +1,4 @@
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/* $NetBSD: bpf.h,v 1.52 2010/01/19 22:08:00 pooka Exp $ */
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/* $NetBSD: bpf.h,v 1.53 2010/01/25 22:18:17 pooka Exp $ */
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/*
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* Copyright (c) 1990, 1991, 1993
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@ -276,6 +276,9 @@ struct bpf_ops {
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extern struct bpf_ops *bpf_ops;
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void bpf_setops(void);
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void bpf_ops_handover_enter(struct bpf_ops *);
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void bpf_ops_handover_exit(void);
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void bpfilterattach(int);
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int bpf_validate(struct bpf_insn *, int);
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@ -1,4 +1,4 @@
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/* $NetBSD: bpf_stub.c,v 1.3 2010/01/19 23:11:10 pooka Exp $ */
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/* $NetBSD: bpf_stub.c,v 1.4 2010/01/25 22:18:17 pooka Exp $ */
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/*
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* Copyright (c) 2010 The NetBSD Foundation, Inc.
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@ -27,18 +27,119 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: bpf_stub.c,v 1.3 2010/01/19 23:11:10 pooka Exp $");
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__KERNEL_RCSID(0, "$NetBSD: bpf_stub.c,v 1.4 2010/01/25 22:18:17 pooka Exp $");
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#include <sys/param.h>
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#include <sys/kmem.h>
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#include <sys/mbuf.h>
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#include <net/bpf.h>
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static void
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bpf_stub_attach(struct ifnet *ipf, u_int dlt, u_int hlen, struct bpf_if **drvp)
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{
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struct laglist {
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struct ifnet *lag_ifp;
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u_int lag_dlt;
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u_int lag_hlen;
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struct bpf_if **lag_drvp;
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TAILQ_ENTRY(laglist) lag_entries;
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};
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static TAILQ_HEAD(, laglist) lagdrvs = TAILQ_HEAD_INITIALIZER(lagdrvs);
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static void bpf_stub_attach(struct ifnet *, u_int, u_int, struct bpf_if **);
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static void bpf_stub_detach(struct ifnet *);
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static void bpf_stub_null(void);
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static void bpf_stub_warn(void);
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static kmutex_t handovermtx;
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static kcondvar_t handovercv;
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static bool handover;
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struct bpf_ops bpf_ops_stub = {
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.bpf_attach = bpf_stub_attach,
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.bpf_detach = bpf_stub_detach,
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.bpf_change_type = (void *)bpf_stub_null,
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.bpf_tap = (void *)bpf_stub_warn,
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.bpf_mtap = (void *)bpf_stub_warn,
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.bpf_mtap2 = (void *)bpf_stub_warn,
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.bpf_mtap_af = (void *)bpf_stub_warn,
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.bpf_mtap_et = (void *)bpf_stub_warn,
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.bpf_mtap_sl_in = (void *)bpf_stub_warn,
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.bpf_mtap_sl_out = (void *)bpf_stub_warn,
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};
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struct bpf_ops *bpf_ops;
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static void
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bpf_stub_attach(struct ifnet *ifp, u_int dlt, u_int hlen, struct bpf_if **drvp)
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{
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struct laglist *lag;
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bool storeattach = true;
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lag = kmem_alloc(sizeof(*lag), KM_SLEEP);
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lag->lag_ifp = ifp;
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lag->lag_dlt = dlt;
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lag->lag_hlen = hlen;
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lag->lag_drvp = drvp;
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mutex_enter(&handovermtx);
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/*
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* If handover is in progress, wait for it to finish and complete
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* attach after that. Otherwise record ourselves.
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*/
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while (handover) {
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storeattach = false;
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cv_wait(&handovercv, &handovermtx);
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}
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if (storeattach == false) {
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mutex_exit(&handovermtx);
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kmem_free(lag, sizeof(*lag));
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KASSERT(bpf_ops != &bpf_ops_stub); /* revisit when unloadable */
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bpf_ops->bpf_attach(ifp, dlt, hlen, drvp);
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} else {
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*drvp = NULL;
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TAILQ_INSERT_TAIL(&lagdrvs, lag, lag_entries);
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mutex_exit(&handovermtx);
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}
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}
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static void
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bpf_stub_detach(struct ifnet *ifp)
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{
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TAILQ_HEAD(, laglist) rmlist;
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struct laglist *lag, *lag_next;
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bool didhand;
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TAILQ_INIT(&rmlist);
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didhand = false;
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mutex_enter(&handovermtx);
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while (handover) {
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didhand = true;
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cv_wait(&handovercv, &handovermtx);
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}
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if (didhand == false) {
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/* atomically remove all */
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for (lag = TAILQ_FIRST(&lagdrvs); lag; lag = lag_next) {
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lag_next = TAILQ_NEXT(lag, lag_entries);
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if (lag->lag_ifp == ifp) {
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TAILQ_REMOVE(&lagdrvs, lag, lag_entries);
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TAILQ_INSERT_HEAD(&rmlist, lag, lag_entries);
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}
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}
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mutex_exit(&handovermtx);
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while ((lag = TAILQ_FIRST(&rmlist)) != NULL) {
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TAILQ_REMOVE(&rmlist, lag, lag_entries);
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kmem_free(lag, sizeof(*lag));
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}
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} else {
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mutex_exit(&handovermtx);
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KASSERT(bpf_ops != &bpf_ops_stub); /* revisit when unloadable */
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bpf_ops->bpf_detach(ifp);
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}
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}
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static void
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@ -59,27 +160,49 @@ bpf_stub_warn(void)
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#endif
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}
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struct bpf_ops bpf_ops_stub = {
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.bpf_attach = bpf_stub_attach,
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.bpf_detach = (void *)bpf_stub_null,
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.bpf_change_type = (void *)bpf_stub_null,
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.bpf_tap = (void *)bpf_stub_warn,
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.bpf_mtap = (void *)bpf_stub_warn,
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.bpf_mtap2 = (void *)bpf_stub_warn,
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.bpf_mtap_af = (void *)bpf_stub_warn,
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.bpf_mtap_et = (void *)bpf_stub_warn,
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.bpf_mtap_sl_in = (void *)bpf_stub_warn,
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.bpf_mtap_sl_out = (void *)bpf_stub_warn,
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};
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struct bpf_ops *bpf_ops;
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void bpf_setops_stub(void);
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void
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bpf_setops_stub()
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bpf_setops()
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{
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mutex_init(&handovermtx, MUTEX_DEFAULT, IPL_NONE);
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cv_init(&handovercv, "bpfops");
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bpf_ops = &bpf_ops_stub;
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}
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__weak_alias(bpf_setops,bpf_setops_stub);
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/*
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* Party's over, prepare for handover.
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* It needs to happen *before* bpf_ops is set to make it atomic
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* to callers (see also stub implementations, which wait if
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* called during handover). The likelyhood of seeing a full
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* attach-detach *during* handover comes close to astronomical,
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* but handle it anyway since it's relatively easy.
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*/
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void
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bpf_ops_handover_enter(struct bpf_ops *newops)
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{
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struct laglist *lag;
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mutex_enter(&handovermtx);
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handover = true;
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while ((lag = TAILQ_FIRST(&lagdrvs)) != NULL) {
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TAILQ_REMOVE(&lagdrvs, lag, lag_entries);
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mutex_exit(&handovermtx);
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newops->bpf_attach(lag->lag_ifp, lag->lag_dlt,
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lag->lag_hlen, lag->lag_drvp);
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kmem_free(lag, sizeof(*lag));
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mutex_enter(&handovermtx);
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}
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mutex_exit(&handovermtx);
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}
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/* hangover done */
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void
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bpf_ops_handover_exit()
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{
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mutex_enter(&handovermtx);
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handover = false;
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cv_broadcast(&handovercv);
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mutex_exit(&handovermtx);
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}
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